Make SetNumThreads apply to the eigen threads. (This creates a dependency on eigen!)

PiperOrigin-RevId: 188504172

1 files changed, 52 insertions, 0 deletions

diff --git a/tensorflow/contrib/lite/kernels/eigen_support.cc b/tensorflow/contrib/lite/kernels/eigen_support.cc
new file mode 100644
index 0000000000..1435a45672
--- /dev/null
+++ b/tensorflow/contrib/lite/kernels/eigen_support.cc
@@ -0,0 +1,52 @@
+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#include "tensorflow/contrib/lite/kernels/eigen_support.h"
+
+#include "third_party/eigen3/Eigen/Core"
+#include "tensorflow/contrib/lite/kernels/op_macros.h"
+
+namespace tflite {
+namespace eigen_support {
+
+struct RefCountedEigenContext {
+  int num_references = 0;
+};
+
+void IncrementUsageCounter(TfLiteContext* context) {
+  auto* ptr = reinterpret_cast<RefCountedEigenContext*>(context->eigen_context);
+  if (ptr == nullptr) {
+    Eigen::setNbThreads(context->recommended_num_threads);
+
+    ptr = new RefCountedEigenContext;
+    ptr->num_references = 0;
+    context->eigen_context = ptr;
+  }
+  ptr->num_references++;
+}
+
+void DecrementUsageCounter(TfLiteContext* context) {
+  auto* ptr = reinterpret_cast<RefCountedEigenContext*>(context->eigen_context);
+  if (ptr == nullptr) {
+    TF_LITE_FATAL(
+        "Call to DecrementUsageCounter() not preceded by "
+        "IncrementUsageCounter()");
+  }
+  if (--ptr->num_references == 0) {
+    delete ptr;
+  }
+}
+
+}  // namespace eigen_support
+}  // namespace tflite